CN100361353C - Method for constituting compact-type He-Ne laser and apparatus thereof - Google Patents

Abstract

The present invention relates to a method and a device for building a compact type helium-neon laser capable of obtaining laser output with larger power. The present invention uses a discharge tube of which the cross section presents a cruciform shape or the multi-cruciform cross sections are symmetrically distributed; mixed gas of helium and neon is excited by using radio frequency discharge, a resonant cavity is stabilized by using two mirrors, and thus, the present invention solves the problem that larger helium-neon laser output can not be obtained under the condition of a short laser tube. The device can be used for occasions, such as laser medicine, laser biology, laser stage lighting, laser intelligence recordation and processing, etc.

Description

A kind of compact He-Ne Lasers apparatus

Technical field the present invention relates to optics and optical engineering field, mainly is that the employing cross section is the discharge tube of a cross or the many star sections of a symmetry distribution and method and the device thereof that rf discharge excitation obtains big He-Ne Lasers power output.

The helium neon laser that background technology is general forms laser by circular cross section He-Ne gas discharge capillaceous.As, one No. 4429399 said helium neon lasers of patent of U.S. US are exactly an example.This laser tube structure will improve laser output power, must increase discharge tube length.When discharge tube is very long, use very inconvenient.China insult one toot to have invented by cross section be the helium neon laser made of the discharge tube of rectangle (patent of invention authorization number 85100563), make the laser output of one meter long device rise to 1.5 times of circular section pipe output, or higher.Its shortcoming is that the long limit of the square-section of pipe can not be oversize, and oversize then discharge instability will use large-sized chamber mirror with the duration limit is oversize, and this is also inconvenient.In addition, radio frequency discharge has been widely used in gas discharge laser, and in 20th century the seventies just successfully be used for helium neon laser (P.W.Smith, Applied PhysicsLetters, V0l.19, No.5,1971,132-134), radio frequency discharge is that special-shaped discharge tube discharge brings certain convenience.

Summary of the invention the objective of the invention is to make up to be provided a kind of and can obtain under shorter discharge tube situation than equal length pipe, helium neon laser that the quarter bend power output is bigger.

The helium neon laser that the constructed high power He-Ne laser that provides of the present invention is made up of the radio-frequency power supply of He-Ne Lasers discharge tube, optical resonator and laser, the discharge tube that it is characterized in that limiting active medium is being a cross or a symmetry many star sections that distribute perpendicular to the axial discharge cross section of discharge tube, and the center of star section is all on the axis of discharge tube.Each star section is made up of two slab region, and the ratio of the length bidimensional yardstick of slab region is 10: 1.Like this, utilize bond length to guarantee enough laser gains, utilize suitably long long limit size that bigger mode volume is provided, the mode volume with discharge tube of many star sections will be very big, can take into account the factors that influence improves power output.Therefore, the laser that this construction method provides is compared with the circular section or the square-section discharge tube of same discharge length, and its power output is much bigger, and facula area is also much bigger.

Advantages such as helium neon laser provided by the invention is compared with existing helium neon laser, and it is big to have power output, and structure is very compact, and cost is low, and the life-span is long, is convenient to produce, and is easy to use.Can use for the application scenario of demand high-power helium-neon lasers such as laser medicine, laser biology, laser stage lighting, laser intelligence record and processing.

Description of drawings Fig. 1 is the schematic diagram of the helium neon laser that provides of this construction method, wherein 1 is the deielectric-coating completely reflecting mirror, 2 is the deielectric-coating partially reflecting mirror, also be laser output mirror, 3 is quartz or glass discharge vessel, the 4 diesis tee sections for symmetrical distribution, 5 is quartz or glass medium bar, they are divided into the diesis district to discharge tube, and 6 is the charge and exhaust pipe of discharge tube, are used for pumping high vacuum and fill helium, neon gaseous mixture.7 for being used for the metal transport tape of radio frequency discharge, and 8 for being used to adjust the inductance coil of discharge homogenizing, and 9 is radio-frequency power supply, and its frequency is generally 10-20MHz.Fig. 2 is the transverse cross-sectional view of discharge tube 3, and a represents that the minor face of a slab region of star section is long among the figure, and b represents the long edge lengths of slab region.Fig. 3 is the schematic perspective view of quartz or glass medium bar 5 among Fig. 1, it is long to be l, shorter slightly than discharge tube, height is h, and h subtracts the poor of a/2 for the discharge tube inside radius, the end is a cylinder, the angle on cross section both sides is θ, when cross only, and θ=90 °, θ=45 ° during two crosses, θ=360 °/4N then during N cross.Fig. 4 is for obtaining the processing schematic diagram that medium strip shown in Figure 3 is drawn, and is a sectional view, and broken circle is represented quartz or glass pole, and solid line is represented after processing the part that keeps, i.e. medium strip, and the radius of curvature of arc S is identical with the radius of curvature of discharge tube 3 inwalls.

Embodiment high power He-Ne laser provided by the invention is by following scheme implementation.Discharge tube 3 employing walls are thicker, pipe is straight and uniform circular quartz of internal diameter or glass tube.Get eight quartz or glass bars that diameter is close with discharge tube 3 inside radius, place on the stabilized platform and fix, both sides are highly being that location side's bar of h clamps it, at first use and be about 20cm, positive mild steel grinding tool for negative cylinder, negative cylindrical curvature radius is identical with the discharge tube inside radius, with grinding tool join diamond dust with a side grinding of pole for and the identical cylinder of pipe 3 internal diameters, again quartz or glass bar are changeed 180 °, with glue that its bottom and platform is temporarily fixing, be about 20cm with another again and have angle theta (should be smaller), deeply join diamond dust it is worn into as shown in Figure 3 bar, all note polishing after twice processing for the mild steel V-shaped groove of h.What a a few hours can process fully and be about 1m generally speaking, quartz or the glass medium bar of high about 12mm.With two symmetric double cross graphite supports eight identical medium strip are fixed in the discharge tube 3, each medium strip two ends are welded to pipe 3 inwalls respectively (are convenient welding, the outside, two ends with each medium strip grinds off a part in advance, English or glass material so that rockfill), from the outside medium strip is imposed spot welding in all the other positions again.But discharge tube operation break-down batch machining, production with diesis shape symmetrical distribution cross section.The ratio of the length limit length of side of four slab region of diesis tee section is 10: 1, this ratio with the length limit of the quarter bend device of Ling Yiming invention is that 5: 1 situation is approaching, and the diesis tee section pipe activation volume among the present invention then may reach about the octuple of quarter bend.After diesis tee section discharge tube processes, then clean with glass cleaning solution, clean repeatedly with deionized water then, after cleaned with its oven dry, again with speculum 1,2 by resonant cavity requirement sealing label in the discharge tube two ends, charge and exhaust pipe with discharge tube is communicated with high vacuum system again, is pumped into high vacuum and (fills helium, neon gaseous mixture behind the 10-6 * 133.3Pa).The resonant cavity of laser can be according to the structure, the parameter that laser transverse mode, power output, stability are waited the selective resonance chamber.The electrode of radio-frequency power supply 9 is two metal transport tapes 7, and when discharge tube surpassed 30cm length, the easily good discharge of acquisition of segmented radio frequency excitation was carried out in general consideration.

For example, use internal diameter 30mm, wall thickness 1.5mm, one of the quartz ampoule of long 1m, get eight diameter 15mm, the quartz pushrod of long 99cm is satisfied with on the platform, with being about 20cm, radius of curvature is that the negative cylinder mild steel grinding tool of 15mm is joined diamond dust one side of eight rods is ground down symmetrically, make highest point grind off 1.5mm, it is 45 ° with angle again, the degree of depth is that the V-type groove mild steel grinding tool of 13.5mm is joined Buddha's warrior attendant sand milling opposite side, can process satisfactory eight medium strip, can obtain the discharge tube of symmetric double cross-like cross-section through assembling and spot welding, each slab region of diesis tee section is wide to be 3mm, long is 30mm, and optical resonator adopts plano-concave sphere inner-cavity structure, concave mirror (reflectivity 99.9%) radius of curvature 3m, the plane mirror transmitance is 1.5%, is extracted into high vacuum (10 through charge and exhaust pipe 6 ^-6* fill He, the Ne gaseous mixture of 0.8 * 133.3Pa after 133.3Pa), the ratio of He and Ne is 7.5: 1, and radio-frequency power supply divides three sections to the discharge tube discharge, and rf frequency is got 10-20MHz, total about 400-500W of injecting power then can obtain bigger 0.6328 μ m laser output.

Device with a cross or many cross-like cross-section of symmetry distribution discharge tube helium neon laser, comprise discharge tube, completely reflecting mirror, partially reflecting mirror, charge and exhaust pipe, radio-frequency power supply, transport tape, inductance coil, with reference to accompanying drawing 1, deielectric-coating completely reflecting mirror 1 is connected with the port of discharge tube 3, deielectric-coating partially reflecting mirror 2 is connected with the another port of discharge tube 3, charge and exhaust pipe 62 several lis away from partially reflecting mirror is being located to be connected be with discharge tube 3, transport tape 7 places the both sides up and down of discharge tube, radio-frequency power supply 9 is connected with transport tape 7, inductance coil 8 is connected in, between the following transport tape 7, the cross section that it is characterized in that discharge tube is many star sections that a star section or a symmetry distribute.The advantage of this device is:

1. this device is a modular appliance, and the dispersion processing difficulty can be produced parts in batches, assembles whole laser in batches.

2. this device can provide bigger gain coefficient and very big active region, so can obtain big He-Ne Lasers power output.

3. extremely compact, easy to use, the transportation of device.

Claims (3)

1, a kind of by helium-neon discharge tube, the helium neon laser that optical resonator and radio-frequency power supply are formed, be characterised in that discharge tube (3) and the region of discharge of the combination of being fixed in the discharge tube (3) 4 or 4N glass or the formation of quartz medium bar with the interior gas medium of discharge tube (3) limit, make region of discharge be a star section perpendicular to the axial cross section of discharge tube (3) or be N star section that is symmetrically distributed, each star section is that two slab region intersect vertically and form, the ratio of the length bidimensional yardstick of slab region is 10: 1, being centered close on the discharge tube axis of slab region, N is the integer more than or equal to 2.

2, according to the described helium neon laser of claim 1, its cross section is that the region of discharge of a star section or N symmetrical distribution star section is that combination restriction by discharge tube (3) and 4 or 4N glass or quartz medium bar forms, be characterised in that these 4 or 4N glass or quartz medium bar are symmetrically distributed in the discharge tube (3), the radius of curvature of its bottom equals discharge tube (3) inside radius, highly deduct the short dimension yardstick (a) of the slab region of 1/2nd star sections for discharge tube (3) inside radius, the drift angle of 4 glass or quartz medium bar is 90 degree, and the drift angle of 4N glass or quartz medium bar is 360 degree/4N, its bottom and to put between pipe (3) inwall fixedly be to be formed by the spot welding between glass and glass or quartz and quartz material, spot welding is that a side that earlier two ends of these 4 or 4N glass or quartz medium bar is contacted with the discharge tube inwall grinds off earlier, then the graphite support fixing down after glass or quartz material are filled out in two ends with glass or quartz medium bar with put pipe (3) inwall and weld, all the other positions of medium strip impose spot welding from discharge tube (3) outside.

3, a kind of nitrogen neon laser apparatus, comprise quartz or glass discharge vessel (3), completely reflecting mirror (1), partially reflecting mirror (2), charge and exhaust pipe (6), radio-frequency power supply (9), metal transport tape (7), inductance coil (8), completely reflecting mirror (1) is connected with an end of discharge tube (3), partially reflecting mirror (2) is connected with the other end of discharge tube (3), charge and exhaust pipe (6) is being connected with discharge tube (3) from partially reflecting mirror (2) number centimeters, metal transport tape (7) places the upper and lower sides of discharge tube (3) to make the radio-frequency power supply electrode and uses, be connected by inductance coil (8) between upper and lower sides metal transport tape (7), radio-frequency power supply (9) is connected with upper and lower sides metal transport tape (7), it is characterized in that perpendicular to the axial region of discharge cross section of discharge tube (3) be a star section or N symmetrical distribution star section, this star section or N symmetrical distribution star section is to be the cross section of the region of discharge that constitutes of 90 degree or 4N drift angle be 360 degree/4N glass or quartz medium bar and the discharge tube (3) that comprises them by 4 drift angles, each star section is intersected vertically by two slab region and forms, on the axis that is centered close to discharge tube (3) of slab region, the ratio of the length two dimension yardstick of slab region is 10: 1, N is the integer more than or equal to 2, the bottom curvature radius of glass or quartz medium bar equals the inside radius of discharge tube (3), the high short dimension yardstick (a) that deducts the slab region of 1/2nd star sections for discharge tube (3) inside radius.

Images